Holocene sea-level changes in the Malay-Thai Peninsula, a tectonically stable environment

The Malay-Thai Peninsula is part of tectonically stable Sundaland, which is the southeast corner of the Eurasian Plate. The Holocene sea-level changes in the region are deduced from a total of 200 dated shoreline indicators. Sea level reached a peak of about 5 m and about 4 m some 5,000 years and 6,000 years ago in Peninsular Malaysia and Thailand. This mid-Holocene transgression was followed by sea-level decrease that took place either gradually, or step-wise with thousand-year periods of stillstand, or more likely in a series of short to medium long periods of regressions and smaller transgressions. During one of the regressions, Late Holocene sea level probably dropped below current datum. Shoreline indicators of pre Mid-Holocene age located between the latitudes of the Langkawi Islands and Phang Nga are anomalously high. These high elevations suggest geoidal relief of up to 40 metres between the northern and southern parts of Strait Malacca.